Mumbai, Jan. 11 -- Forensic analysis shows 62 broking firms may have enjoyed preferential access to servers of National Stock Exchange of India Ltd (NSE), and not just the three that have been served showcause notices. This is according to three forensic audit reports by EY India Ltd, Deloitte Touche Tohmatsu India Llp and International School of Business (ISB). Mint reviewed excerpts of these reports.

The case pertains to some broking firms having preferential access to NSE's high-speed algorithmic trading platform through its co-location service. The Securities and Exchange Board of India (Sebi) has so far issued show-cause notices to only three-OPG Securities, its associate GKN Securities and Way2Wealth Brokers Pvt Ltd.

The reports s...